There are many applications in which controlled switching of a large plurality of electrical conductors, e.g. 24 or more conductors, is desired or necessary. In many such switching applications, particularly those involved in data communications where rearrangement of communications facilities is to be accomplished by electrical switch means, it is often desirable to provide for remote operation of the switch means, and/or to provide rather complex sets of operations of various switch means from a single location. Either of these operations can be accomplished by means of separate electrical controls for each switch means, but at the cost of great complexity in control equipment. It is also desirable to provide for straightforward mechanical actuation of the switch means; this is desirable, for example, to accommodate failure of the electrical control system due to power outage or other malfunction which prevents the electrical control system from operating properly. Mechanical control of the switching means may also be a convenience in cases where the electrical control is at a remote site and the operator wishes to activate the switching means from his position immediately adjacent the switching apparatus, rather than from the remote control position. The desired mechanical operation of a large number of switches can be provided conventionally by using a corresponding large number of switch actuators such as switch buttons, with attendant complexity. However, so far as is known there has been no apparatus available which would provide simple and inexpensive switching of lines containing a large number of conductors, by electrical control or by manual control at the option of the operator.
While there are a large variety of instances in which such apparatus will have application, for simplicity and clarity of exposition the present invention will be described particularly with respect to the following specific application thereof.
In our co-pending application Ser. No. 656,597 entitled "Connecting And Switching Systems, And Switching Apparatus Suitable For Use Therein", filed Feb. 9, 1976 and now U.S. Pat. No. 4,037,186, issued July 19, 1977, there is shown a system wherein a modem is connected to local equipment, such as a computer, by way of a line comprising a plurality of conductors extending through a corresponding plurality of magnetically-operable switches. The multi-conductor line also extends from at least one side of the switching element to multi-contact plug receptacles into which the plug of a patchcord can be inserted to transfer the signals on the multi-conductor lines to any other desired position. The arrangement in the cited patent application is such that, in response to insertion of the plug into the receptacle, the switches normally connecting the modem to the local equipment are automatically opened, for purposes and reasons fully set forth in that patent application, the switches reclosing automatically when the plug is removed. This is accomplished by causing the inserted plug to change the position of a panel which changes the magnetic flux reaching a set of magnetically-operable reed switches.
In some cases, to which the present invention is applicable, one may desire or require the capability of switching the multi-conductor line extending to the local equipment to another, substitute local equipment. For example, where the local equipment is a main computer it may be desirable, in the event of breakdown, malfunction or routine maintenance of the main computer, to substitute a back-up computer for it, at least temporarily. This capability may be provided by inserting a first multi-conductor switch arrangement in the line to the main computer and a second multi-conductor switch arrangement in the line to the back-up computer, and providing switch control means which will open the line to the main computer and close the line to the back-up computer when substitution of the back-up computer is desired, and vice versa.
In such cases, it may be desirable to be able to operate a device which will act electrically to substitute the back-up computer in the connection to the above-mentioned modem, and it may in fact be desirable to switch one or more other modems to the back-up computer by electrical means. Further, in the event of breakdown of the electrical control system it would be advantageous to be able to accomplish this substitution of the back-up computer by mechanical means not dependent upon the existence of electrical supply power.
While the relatively-simple application with respect to which the present invention will be particularly shown and described has been selected for simplicity of description and is rather rudimentary in its overall functions, it will be understood that the invention may be applied to extremely complex control systems of a large variety of types and classes, as will occur to one skilled in the art upon a reading of this specification.
Accordingly, it is an object of this invention to provide new and useful apparatus for electrically controlling the switching of plural-conductor electrical lines.
Another object is to provide such switching in response to an electrical control signal, in a manner which is particularly simple and reliable.
A further object is to provide simple mechanical control of said switching in addition to said electrical control, also in a manner which is relatively simple and reliable.
Still another object is to provide such a system in which either mechanical or electrical control of multi-conductor lines may be exerted by an operator, at his option, and in which the mechanical arrangement will still be fully operative if the electrical control arrangements should become inoperative or disconnected.